Connection Reset in TCPDUMP

asked 2022-11-21 08:45:25 +0000

KBJR gravatar image

updated 2022-11-21 10:28:32 +0000

grahamb gravatar image

Hi,

Attached is the TCPDUMP from WebLogic 10.3.6 OS(Hosted on Oracle Linux 64) to Oracle DB 11g Port 1521(Hosted on Oracle Linux 64).We are always receiving hang on WLS. Captured Packet shows Connection Reset. In this case, which peer is reseting the connection ?

Is it Weblogic reseting the connection when no response from DB or DB itself reseting the connection ?

Any feedback on this ?

Below is the 2 Packet Details of Dump.There are several occurred in TCPDUMP.

Summary

81536   2207.351784 172.16.100.106  172.16.100.115  TCP 66  24194 → 1521 [RST, ACK] Seq=234937 Ack=6781 Win=30208 Len=0

Detail

Frame 81536: 66 bytes on wire (528 bits), 66 bytes captured (528 bits)
Ethernet II, Src: HewlettP_73:f5:f8 (ac:16:2d:73:f5:f8), Dst: HewlettP_74:13:b4 (ac:16:2d:74:13:b4)
Internet Protocol Version 4, Src: 172.16.100.106, Dst: 172.16.100.115
Transmission Control Protocol, Src Port: 24194, Dst Port: 1521, Seq: 234937, Ack: 6781, Len: 0
    Source Port: 24194
    Destination Port: 1521
    [Stream index: 48]
    [TCP Segment Len: 0]
    Sequence number: 234937    (relative sequence number)
    Acknowledgment number: 6781    (relative ack number)
    Header Length: 32 bytes
    Flags: 0x014 (RST, ACK)
        000. .... .... = Reserved: Not set
        ...0 .... .... = Nonce: Not set
        .... 0... .... = Congestion Window Reduced (CWR): Not set
        .... .0.. .... = ECN-Echo: Not set
        .... ..0. .... = Urgent: Not set
        .... ...1 .... = Acknowledgment: Set
        .... .... 0... = Push: Not set
        .... .... .1.. = Reset: Set
            [Expert Info (Warning/Sequence): Connection reset (RST)]
                [Connection reset (RST)]
                [Severity level: Warning]
                [Group: Sequence]
        .... .... ..0. = Syn: Not set
        .... .... ...0 = Fin: Not set
        [TCP Flags: ·······A·R··]
    Window size value: 236
    [Calculated window size: 30208]
    [Window size scaling factor: 128]
    Checksum: 0x21ed [unverified]
    [Checksum Status: Unverified]
    Urgent pointer: 0
    Options: (12 bytes), No-Operation (NOP), No-Operation (NOP), Timestamps

Summary

281168  6792.352201 172.16.100.106  172.16.100.115  TCP 66  24461 → 1521 [RST, ACK] Seq=4692 Ack=5358 Win=30208 Len=0

Detail

Frame 281168: 66 bytes on wire (528 bits), 66 bytes captured (528 bits)
Ethernet II, Src: HewlettP_73:f5:f8 (ac:16:2d:73:f5:f8), Dst: HewlettP_74:13:b4 (ac:16:2d:74:13:b4)
Internet Protocol Version 4, Src: 172.16.100.106, Dst: 172.16.100.115
Transmission Control Protocol, Src Port: 24461, Dst Port: 1521, Seq: 4692, Ack: 5358, Len: 0
    Source Port: 24461
    Destination Port: 1521
    [Stream index: 57]
    [TCP Segment Len: 0]
    Sequence number: 4692    (relative sequence number)
    Acknowledgment number: 5358    (relative ack number)
    Header Length: 32 bytes
    Flags: 0x014 (RST, ACK)
        000. .... .... = Reserved: Not set
        ...0 .... .... = Nonce: Not set
        .... 0... .... = Congestion Window Reduced (CWR): Not set
        .... .0.. .... = ECN-Echo: Not set
        .... ..0. .... = Urgent: Not set
        .... ...1 .... = Acknowledgment: Set
        .... .... 0... = Push: Not set
        .... .... .1.. = Reset: Set
            [Expert Info (Warning/Sequence): Connection reset (RST)]
                [Connection reset (RST)]
                [Severity level: Warning]
                [Group: Sequence]
        .... .... ..0. = Syn: Not set
        .... .... ...0 = Fin: Not set
        [TCP Flags: ·······A·R··]
    Window size value: 236
    [Calculated window size: 30208]
    [Window size scaling factor: 128]
    Checksum: 0x21ed [unverified]
    [Checksum Status: Unverified ...
(more)
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Comments

Is there a packet capture before the RST? The screenshots show that the client sent a RST, but it isn't clear if it was something the server sent.

BigFatCat gravatar imageBigFatCat ( 2022-11-21 10:24:22 +0000 )edit

Hi, Are you referring client here 172.16.100.106(Weblogic) and Server 172.16.100.115(DB) ? Below are the Packet(81535,281167) captured before RST -

81535   2142.919699 172.16.100.106  172.16.100.115  TCP 66  53941 → 1521 [ACK] Seq=3223 Ack=1873 Win=236 Len=0

81536   2207.351784 172.16.100.106  172.16.100.115  TCP 66  24194 → 1521 [RST, ACK] Seq=234937 Ack=6781 Win=30208 Len=0

281167  6755.457828 172.16.100.106  172.16.100.115  TCP 66  13580 → 1521 [ACK] Seq=7579402 Ack=221598170 Win=8341 Len=0

281168  6792.352201 172.16.100.106  172.16.100.115  TCP 66  24461 → 1521 [RST, ACK] Seq=4692 Ack=5358 Win=30208 Len=0

81535

Frame 81535: 66 bytes on wire (528 bits), 66 bytes captured (528 bits)
Ethernet II, Src: HewlettP_73:f5:f8 (ac:16:2d:73:f5 ...
(more)
KBJR gravatar imageKBJR ( 2022-11-21 11:05:50 +0000 )edit

**contd from last comment

281167

Frame 281167: 66 bytes on wire (528 bits), 66 bytes captured (528 bits)
Ethernet II, Src: HewlettP_73:f5:f8 (ac:16:2d:73:f5:f8), Dst: HewlettP_74:13:b4 (ac:16:2d:74:13:b4)
Internet Protocol Version 4, Src: 172.16.100.106, Dst: 172.16.100.115
Transmission Control Protocol, Src Port: 13580, Dst Port: 1521, Seq: 7579402, Ack: 221598170, Len: 0
    Source Port: 13580
    Destination Port: 1521
    [Stream index: 8]
    [TCP Segment Len: 0]
    Sequence number: 7579402    (relative sequence number)
    Acknowledgment number: 221598170    (relative ack number)
    Header Length: 32 bytes
    Flags: 0x010 (ACK)
        000. .... .... = Reserved: Not set
        ...0 .... .... = Nonce: Not set
        .... 0... .... = Congestion Window Reduced (CWR): Not set
        .... .0.. .... = ECN-Echo: Not set
        .... ..0. .... = Urgent: Not set
        .... ...1 .... = Acknowledgment: Set
        .... .... 0... = Push: Not set
        .... .... .0.. = Reset: Not set
        .... .... ..0. = Syn: Not set
        .... .... ...0 = Fin: Not set
        [TCP Flags: ·······A····]
    Window size value: 8341 ...
(more)
KBJR gravatar imageKBJR ( 2022-11-21 11:06:27 +0000 )edit

Thank you. Sorry, I wasn't clear with my question. What is needed is the two-way flow between the client and server for the sessions that reset. This could explain why the reset was sent or if it is a bug.

BigFatCat gravatar imageBigFatCat ( 2022-11-21 18:42:16 +0000 )edit

I will try to get TCPDUMP for DB side.

KBJR gravatar imageKBJR ( 2022-11-22 04:49:29 +0000 )edit